A family in Portland has made a prehistoric find in their front yard after digging up bones from a mastadon.

The family's home has turned into a makeshift museum.

In a pretty typcial American garage: a Ford Focus, a set of golf clubs, a broom, and bones of a mastadon long dead.

The bones were discovered in the muck when they hired an excavator to dredge their pond.

Their find was authenticated by a University of Michigan professor who estimated that the beast lived between ten and thirteen thousand years ago.

"He looked at it right away and he was pretty excited because he just started putting the pieces together like a little puzzle," said the homeowner, Annette Schneider.

"What we thought was a tailbone was actually something totally different," Schneider said.

They're donating the collection to the U of M museum, where the remains will be better preserved.